"Samsung's recent Android 4.1.2 upgrade for the Galaxy Note 10.1 adds power and flexibility to the company's unique offering of Android multiwindowing features. With this update, the Galaxy Note 10.1 can run up to 16 multiwindow-enabled Android apps at once, Windows/Mac-like, on a single screen. Apps endowed with Samsung's multiwindow technology are usable in three viewing modes: full screen, dual view, and cascade view." There are already some complaining this represents a dangerous fork of Android. I thinks it's a step in the right direction.

What dozend of background tasks you refer too? At Android apps in background may closed anytime and are restored when you switch back making them irrelevant for battery.

Only exceptions are services which register themselfs so Android does keep them running even in background. There are not dozend of them. There are usually zero as default (except you copy a file or download in which case a service is running till the job is done).

The argument with manually managing closing apps to save battery is not really one. Just move them to background and trust the system to close them if they consume to much mem/cpu/battery. No point in doing it manually except for your own feeling of control and habits from other OS's.